Triangle-protractor



July 1934. Q J, WOODS TRIANGLE PROTRACTOR Filed July ll, 1950 INVENTOR. S/C/MUZ d; l/I/S @TURA/EY au ZM lPatented .Fully 10, 1934 EES PATENT GFFICE 3 Claims.

rihis invention relates to a novel instrument designed to be used. by draftsmen, engineers, and the like; to take the place of triangles and protractors.

The triangles, commonly used by draftsmen, engineers, and the like, are of xed shape and are usually of two types, the forty-nyc degree triangle and the thirty-sixty degree triangle. In using these triangles, however, lines can be drawn at only a few angles, and when it is desired to draw lines at other angles resort is had to the use of a protractor. This procedure not only necessitates the use of a plurality of instruments, but oftimes results in the production of inaccurate work since some skill and patience is necessary to obtain accurate results with a protractor.

rlhe principal object of the present invention is to provide a novel drafting instrument or triangle-protractor which is capable of performing the combined functions of a triangle and protractor.

Another object o1" the present invention lies in the provision of a drafting instrument, which, when set to be used as a right angled triangle, has a true exterior edge contour with no parts projecting beyond the outer edges of the triangle to interfere with drawing lines along any edge thereof, or to prevent any edge from being placed against a T -square or parallel straight edge; said instrument when set at any other angle having no parts projecting beyond the outer edge of its base, or beyond theV outer edge of the arm which determines the angle at which the instru- A ment is set.

Still another object of the present invention is to provide a novel instrument of the above character having arms with flat sides, and with the respective sides of the arms lying in a common plane or ush with one another, whereby the instrument may be used with either side against the work paper.

A fourth object of the present invention lies in the provision of an instrument of the above character which is oi simple, compact construction, and which has an angle indicator that moves through a greater number of degrees than the arm which determines the setting of the instrument, thereby spreading the graduations so that they are very legible and enabling the easy and rapid setting of the instrument to' any angle desired.

Other objects of this invention, not at this time more particularly enumerated, will be clearly understood from the following detailed descripof the same.

The invention is clearly illustrated in the accompanying drawing, in which:-

Fig. l is a plan view of the novel triangleprotractor of this invention, the full lines showing the instrument set for use as a right angled triangle, while the dot and dash lines show the instrument set at forty-live degrees and at zero degrees; D

Fig. 2 is an enlarged sectional view, taken along line 2 2 of Fig. l, looking in the direction of the arrows;

Fig. 3 is an enlarged fragmentary view of a portion of the structure of Fig. l, with parts broken away or omitted;

Fig. 4 is a sectional View, taken along line 4 4 of Fig. l;

Fig. 5 is a sectional View of a slightly modied form of arm section; and

Fig. 6 is a side View of the structure shown in Fig. 5.

Similar characters of reference are employed in all of the above described views, to indicate corresponding parts. o'

Referring now t0 Figs. l to i of the drawing, the reference numeral l designates the novel drafting instrument or triangle-protractor of this invention as a whole. instrument l comprises abase 2 of U-shaped cross section open at its top edge 3' and end edges 4 and 5 and closed at its` bottom edge 6. A portion of the side walls of the base 2 are deiiected inwardly providing exterior recesses 7 as shown in Figs. 1 and 4 to strengthen the base 2 and to retain the side walls in proper spaced relation. Reoesses '7, andrparticularly iinger grip apertures 8 provided in base 2 enable the ready gripping of the triangle-protractor in use. The bottom edge 6 of the base 2 is straight to adapt the same to slide along a straight edge or T-square, such sliding motion of the base being easily accomplished through use of. a finger grip 8.

The end edge l of the base 2 extends upwardly from the bottom edge 6 at an oblique angle, which angle is illustrated as an angle of sixty degrees in the drawing, although this angle may be of some other value, for example, forty-five degrees, ifl desired. As shown in full lines Fig. 1, an hypothenusal arm extends upwardly from base 2V parallel to the end edge 4 and has its outer edge flush with the edge 4, so that this arm when in the full line position forms, inerect, a continu-ation of'th'e edge 4, andtogether with-this-edg-eprovides a continuous straight ruling edge extending at an angle of sixty degrees with the bottom edge 6 of base 2. The hypothenusal arm comprises a lower section 9 and an upper section 10 which are hingedly connected by a pivotal pin or hollow rivet 1l, the axis of which is located exactly on line with the inner edges of the sections 9 and 10.

The lower end portion 12 of section 9 is of reduced thickness and projects inwardly between the sides of base 2 and is pivotally connected to this base by a pivotal pin or hollow rivet 13. (See Figs. 1 and 2.) The upper end portion of section 9 carries a segmental plate 14 provided with an angle scale 15 which is concentric with the axis of the pivotal pin or rivet 11. It will be noted that ninety degrees of angle scale 15 is spread over substantially one hundred and eighty actual degrees, thereby spreading the angle scale out so that the same is readily readable. Segmental plate 14 is illustrated as having an edge portion projecting into a recess or slot 16 provided in section 9 and is fixed within this slot as by rivets 17. It is apparent that the plate 14 may be formed integral with section 9, if desired.

The pivotal pin or rivet 11 extends through an aperture in segmental plate 14 and through bearing apertures in two similar arm plates 10 and 10" forming the section 10 of the hypothenusal arm. The arm plates 10 and 10 forming section 10 are positioned on opposite sides of the segmental plate 14, and these arm plates 10 and 10" are adapted to sweep over the angle scale 15 as sections 9 and 10 are moved angularly with respect to one another about rivet 11. Arm plates 10 and 10 are formed with beveled portions forming an indicator 18. The section 10 carries a clamp screw 19 having a clamp nut 21, which, upon being tightened, is adapted to lock the section 19 upon the segmental plate 14, whereby indicator 18 is held at any desired reading on angle scale 15.

The at head 22 of clamp screw 19 and the inner end of clamp nut 21 rest within circular recesses 23 provided in the arm plates 10 and 10". The exterior surface of head 22 is flush with the side of arm plate 10', thereby enabling the triangle-protractor to be placed upon the Work sheet without interference from this head. The shank of clamp screw 19 extends through a semi-annular slot 24 provided in the segmental plate 14. The portion of the shank of clamp screw 19 which lies within slot 24 is enlarged to form a substantially rectangular shoe 25 which by engaging the edges of the slot 24, prevent the unwarranted turning of the clamp screw 19. The clamp screw 19 is insertable through the section 10 from either side of the section, and thereby enables the triangle-protractor to be reversed so that either side of this instrument may be used against the paper.

The upper portions of the arm plates 10 and 10" overlie the sides of the web portion 26 of a protractor arm 27. The protractor arm 27 is the arm of the instrument which determines the angle at which the same is set. The upper portions of arm plates 10 and 10 are pivotally connected to the web portion 26 as by a pivotal pin or hollow rivet 28. The upper edge 29 of protractor arm 27 is illustrated as beveled at an angle of thirty degrees with respect to the longitudinal axis of this arm, so that the instrument forms a right angled triangle, which triangle is illustrated in full lines in Fig. 1, the upper edge 29 being in eiect a continuation of the outer edge of section 10. In other words, as shown in Fig. l, the edge 4 of the base 2, the hypothenusal arm and the upper edge 29 are all in alignment and provide a single straight edge forming the hypothenuse of a right triangle, having the protractor arm 27 and the base 2 for its legs. The protractor arm 27 extends at right angles to the base 2 and has its web portion 26 between the sides of this base. A pivotal pin or rivet 30 serves to pivotally connect the protractor arm 27 with the sides of base 2.

It will be noted that the pivotal pins 18 and 28 are illustrated as positioned respectively on the longitudinal axes of sections 9 and 1G of the hypothenusal arm, whereas the pivotal pin 1l is located in line with the inner edges of the sections 9 and 10. This construction provides two ninety degree (90) positions on the scale 15. In forming the right angled triangle of Fig. 1, the indicator 18 is set on that 99 mark which causes sections 9 and 10 to be in alignment. With the instrument set as shown in full lines in Fig. 1, if clamp nut 21 is loosened and the sections 9 and 1G turned outwardly slightly toward the broken line positions, the pivotal pin 11 will initially move into alignment with pins 13 and 28 causing protractor arm 27 to turn toward the right somewhat, so that this arm will extend at an angle that is slightly over ninety degrees with base 2. 'Ihe indicator 18 is now between the two 6 marks. Continuous outward movement of sections 9 and 10 will cause pin 11 to again move out of alignment with pins 13 and 28, thereby causing arm 27 to reverse its direction of movement and, moving towards the left, will make a ninety degree angle with base 2 when the indicator 18 is on the second 907 mark.

In use, when the indicator 18 of arm plate 10 overlies the ninety degree mark on angle scale 15, the outer edge of protractor arm 27 extends upwardly at right angles to the bottom edge 6 of base 2. In other words, when the outer edge of protractor arm 27 is at ninety degrees with the bottom edge 6, the indicator scale will show a ninety degree spread of the sections 9 and 10 of the hypothenusal arm. With the instrument as set in the full line position or" Fig. 1, a -39 degree triangle is provided which may be used as an ordinary triangle. When it is desired to draw aline at any angle other than ninety degrees with respect to the bottom edge 6 of base 2, it is merely necessary to loosen screw 21 somewhat, and swing sections 9 and 10 of the hypothenusal arm outwardly, as shown in dotted lines in Fig. 1, thereby collapsing this arm and causing the protractor arm 27 to move toward the left while turning about the pivotal rivet 30. If it is desired, for example, to draw a line at an angle of forty-five degrees with respect to the bottom edge 6, the sections 9 and 10 are swung outwardly until the indicator 18 overlies the orty-ve degree mark on the angle scale 15, in which position the protractor will make the desired angle of forty-five degrees with respect to the base 2, as illustrated in dot and dash lines in Fig. l.

It will be noted from viewing this gure, that a line may be drawn along the outer edge of the protractor arm at any angle between Zero and ninety degrees. By turning the instrument over so that its opposite side engages the paper, lines extending at right angles to those produced in the first position of the tinstrument, are obtained. In turning this instrument over it is merely necessary to remove the clamp screw and nut and to reinsert the clamp screw through the opposite side of the instrument.

With the base 2 resting upon a T-square or straight edge, the novel triangle-protractor may be slid along for use over any portion of the work sheet desired. Inasmuch, as it is merely necessary to manipulate a single clamp screw to obtain the varying angles, the instrument is easy to operate. Since the ninety degrees of graduation of the angle scale is spread over approximately one hundred and eighty actual degrees, each individal degree mark is well spaced from the marks of adjacent degrees, thereby enabling the easy setting of the instrument to any angle desired.

It Will be noted, that the novel instrument of this invention, when in the form illustrated in full lines in Fig. 1 or with the indicator set at ninety degrees, may be used as a -30 triangle. Should the end edge 4 of the base make an angle of forty-five degrees with the bottom edge 6, the novel instrument will form a forty-five degree triangle. When in this full line position, no portion of the instrument projects externally of the outer edges of the arms or base.

If desired, the upper section 10 of the hypothenusal arm instead of being made in two parts or plates 10 and 10, may be made as a single unit as illustrated in Fig. 5. In this gure the plates l0 and 10 are integrally joined by a cross member 32.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be ,i made without departing from the scope thereof,

it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:-

1. An instrument of the character described having, a base, an arm movably connected to said base adjacent one end thereof, a second arm movably connected to said base adjacent the other end thereof, said second arm being connected at its other end to the free end of said first named arm and comprising a pair of hingedly connected sections, an angle scale disposed around the hinged connection of said sections and clamping means for locking said sections in xed relation with respect to one another and with respect to any point on said scale, whereby said iirst named arm is held at any desired angle from zero to ninety degrees with respect to said base.

2. An instrument of the character described having, a base, an arm movably connected to said base adjacent one end thereof, a second arm movably connected to said base adjacent the other end thereof, said second arm being connected at its other end to the free end of said rst named arm and comprising a pair of hingedly connected sections, a segmental plate provided on one of said sections, a ninety degree angle scale depicted on said segmental plate and extending through substantially one-hundred and eighty actual degrees, and clamping means carried by the other of said sections and arranged for clamping said other section to said segmental plate at any point on said angle scale, whereby said iirst named arm is held at any desired angle from zero to ninety degrees with respect to said base.

3. A triangle-protractor having, a base, a protractor arm pivotally connected at one end to an end of said base, and an hypothenusal arm pivotally connected at one end to the opposite end of said base and at its other end to the free end of said protractor arm to normally extend straightly between said base and protractor arm to hold these parts at right angles and to form therewith a triangle having an uninterrupted periphery, said hypothenusal arm comprising pivotally connected sections, said sections being movable angularly with respect to one another, whereby said protractor arm may be caused to assume varying angles between zero and ninety degrees with respect to said base as said sections are turned through substantially one hundred and eighty degrees with respect to one another, .and scale means positioned at the pivotal connection of said sections and indicating directly the angle made by said protractor arm with respect to said base.

SAMUEL J. WOODS. 

